Cyclosporiasis outbreak in Michigan surpasses 4,000 cases as source remains unidentified

Michigan health officials reported 4,312 cyclosporiasis cases and 102 hospitalizations as of July 16, 2026, in an unusually large outbreak that began on May 1, 2026. While lettuce is a suspected source, the Food and Drug Administration has not identified a specific supplier. Nationally, the Centers for Disease Control and Prevention has confirmed 1,645 cases across 34 states, with 141 hospitalizations and no deaths, while investigating 5,100 potential cases.

Michigan cyclosporiasis outbreak scale

• ▪The cyclosporiasis outbreak in Michigan has resulted in 102 hospitalizations as of July 16, 2026
• ▪Michigan health officials reported 4,312 cases of cyclosporiasis on July 16, 2026, representing an increase of 550 cases from the previous day

Cyclospora parasite transmission methods

• ▪Cyclosporiasis can also be transmitted through the consumption of water contaminated with feces
• ▪Cyclosporiasis is a parasitic intestinal infection typically contracted by consuming raw fruits and vegetables contaminated with feces

Gastrointestinal symptoms of cyclosporiasis

• ▪No deaths have been reported from the cyclosporiasis outbreak that began on May 1, 2026, despite its gastrointestinal severity
• ▪Cyclosporiasis is an intestinal illness that causes gastrointestinal symptoms such as diarrhea and nausea

Outbreak source investigation efforts

• ▪Michigan health officials identified lettuce as a potential source of the cyclosporiasis outbreak, but no specific produce, grower, or supplier has been linked
• ▪The Food and Drug Administration is conducting traceback investigations on multiple produce items, including lettuce, to determine the outbreak's source

Multi-state case distribution

• ▪The U.S. Centers for Disease Control and Prevention was investigating 5,100 possible cyclosporiasis cases as of July 15, 2026
• ▪The cyclosporiasis outbreak, which began on May 1, 2026, is centered in Michigan, with Ohio and New York also reporting high numbers of cases
• ▪The U.S. Centers for Disease Control and Prevention confirmed 1,645 cases across 34 states and 141 hospitalizations as of July 15, 2026